Searching for Planets Orbiting $\epsilon$~Eridani with JWST/NIRCam

TL;DR

This study used JWST/NIRCam to search for planets around extepsilon~Eridani, setting new upper limits on planet brightness and disk emission, and evaluating observation strategies, but found no planets.

Contribution

First application of JWST/NIRCam coronagraphy to extepsilon~Eridani, providing improved upper limits and assessing the 3-roll observation strategy's effectiveness.

Findings

No planets detected at the targeted locations.

Established new upper contrast limits at 4 μm.

Observed a faint surface brightness signal consistent with disk scattering.

Abstract

We present observations of \epseri~with the JWST/NIRCam coronagraph aimed at imaging planets orbiting within this system. In particular, these observations targeted (1) the Jupiter-like planet, first detected orbiting at 3.5 AU with radial velocity observations, and (2) the planet postulated to be responsible for carving the edges of \epseri's outer ring, expected to orbit at 40-50 AU. However, no point sources were detected at a statistically significant level. We report new, improved upper limits at 4 $\mu$m: $\sim$1e-7~contrast at 1\arcsec, and $\sim$2e-8~beyond 5\arcsec. The latter contrast limit precludes Saturn-mass planets at separations $>$16~AU given current models. We also report upper limits for \epseri's disk emission at 4 $\mu$m. While the radial surface brightness profile shows no evidence of emission, we detect a 1-$\sigma$ surface brightness signal on the east side of the system, consistent with forward scattering emission expected for \epseri's disk inclination. Finally, we evaluate the performance of the 3-roll observation strategy, which was first employed in these observations: the gains in contrast are modest, with 20-30\% improvements with respect to the conventional 2-roll strategy.